Freedom Fighters are sneaky soldiers good at destroying enemy buildings. They aren't professional troops but while their weapons are a bit weaker they make up for that by employing sneaky guerrilla tactics (which mean defensive buildings won't shoot them).

"A freedom fighter is someone who fights against someone they consider a foreign occupying power. The term came into use in the decades after WWII, an era of decolonization and widespread uprisings imperial rule. Freedom fighters tend to engage in asymmetrical warfare against superior occupying forces and therefore resort to guerrilla tactics as the likelist means of achieving victory".